Gyro erecting system



Aug. 1, 1950 w. A. REICHEL ETAL GYRO ERECTING SYSTEM Filed May 18 1948 2 Sheets-Sheet l By JE [/778/50/7.

Aug. 1, 1950 w. A. REICHEL ETAL 2,516,912

and ERECTING SYSTEM Filed May 18; 1948 2 Sheets-Sheet 2 our/ ur HME INVQVTORS W A? Few/7d 8 75m er 90/7 flw Patented Aug. 1, 1950 UNITED STATES PATENT OFFICE GYRO ERECTING SYSTEM Application May 18, 1948, Serial No. 27,784

7 Claims.

This invention relates to vertical seeking reference systems and more particularly to a pendulum' adapted to control the operation of gyroerecting motors.

An object of the invention is to provide a pendulum construction wherein the pendulum produces an erecting force proportional to its displacement in a limited range and wherein the pendulum may be highly damped by immersion of the moving parts in oil so as to prevent too rapid a response to acceleration and deceleration forces.

Another object is to provide a pendulous erecting system which has its vertical seeking components sealed in a chamber containing fluid damping means.

A further object is to provide a simple and compact erecting system which may be contained physically Within an axial chamber of a gyro rotor.

Various other objects and advantages will be apparent as the nature of the invention is more fully disclosed hereinafter.

In accordance with the present invention, a pendulum includes a suspended mass of magnetic material having a bottom surface disposed 1 to swing over a plurality of radially disposed magnetic cores so as to vary the reluctance of different magnetic paths in accordance with the pendulums deviation from true vertical. The diilerential effect of the reluctances of the various paths produces a signal which controls the gyro-erecting motors. The pendulum and the magnetic material and cores are enclosed in a casing which may be filled with oil or other liquid for damping purposes.

Although the novel features which are characteristic of this invention are pointed out more particularly in the claims, the nature of the invention will be better understood by reference to the following description, taken in connection I! to the bottom of a gyro housing I2, indicated by dash lines, and carries a tube l4 extending upwardly through a bore iii in the gyro rotor 16.

Inasmuch as the gyro may be of standard construction the details thereof are not set forth herein. A gyro oi the type illustrated in the copending application of Smith and Brigham, Serial No. 753,392, filed June '7, 1947, for Vertical Seeking Gyro may be used. It is to be understood that the gyro is mounted on suitable gimbals for movement about normal axes l8 and I9 (Fig. 4) and that erection motors 2D and 2! are disposed to apply precessing torques about the respective axes.

The top of the tube 34 is closed by a plug 25. The plate it carries a case 26 of non-magnetic material or magnetic material if needed for shielding, which forms a closed chamber 21 to receive the magnetic structures and pendulum to be described. A member of magnetic material comprising a central core 28, a bottom disc 24 and four peripheral cores 29, 30, 3} and. 32 is secured in the case 26. Windings 33, 34, 35, 38 and 31 are disposed about the respective cores to form a central energizing winding and four radially spaced pick-up windings. A cap 38 of magnetic material is associated with the central core 28 to provide an annular pole face of comparatively large area. The cores 29, 30', SI and 32 terminate in arcuate pole faces above the plane of the cap 323.

The case 25 carries a pin 40 which extends axially of the tube 14 and is formed with a point 4| at its top. A pendulum tube 42 is suspended from the point All by a jewel bearing 43 secured in a cup 44 held in the end of the tube 42. A screw 45 threaded in the plug 25 normally has a slight clearance from the bearing 43 but serves as a stop to prevent the bearing from unseating when the housing becomes inverted and then it serves as the pivot.

The pendulum tube 42 extends downwardly around the pin 40 and carries at its free end an annular disc 41 of magnetic material. An annular metallic ring 48 is mounted on the disc 41 to provide the desired pendulous mass. The lower surface of the disc 41 includes an inner horizontal surface 41a which is spaced from the cap 38 by a small clearance for full deflection of the pendulum. The surface 41a then tapers to a suitable clearance with the ends of the cores 29, 30, 31 and 32. The diameter of the disc 41 is such that, when suspended in central position, it slightly overlaps the inner edges of the cores 29, 30, 3| and 32. The surface 41a may be spherical to the plate ll! forms a stop to limit the movement of the disc 41. Ring 53 may be an integral part of the plate l0.

Winding 33 carried by the central core 28 and cap 38 is an exciting winding connected to a A ring 50 of non-magnetic material attached source of alternating current. It will be readily I understood then, that the magnetic field set up by winding 33 forms a magnetic circuit including core 28, cap 38, discid'l, air gaps and the four parallel return paths. through .identicalcore members 29, 30, 3| and 32. I

This magnetic circuit is employed for the induction in coils 34, 35, 3E and 3! of voltages varying in accordance'with the reluctances of the several magnetic circuits. due to the variable air gap space between disc 4'! and each of the cores 29, 30, 3| and 32. I

1 When. the pendulum is vertical and at rest,

disc member 4? lays symmetrically above cap 38 1' motors and as shown in Fig. 4.

Referring to Fig. 4, the coils 35 and 31 are shown as connected differentially in series be- This differential eifect is utilized-to actuate the erecting However, when the 1- tween posts 52 and 53 which are in turn connected by leads 54 and 55 to a control amplifier 56. The control amplifier 56 is connected to supply exciting current to phase winding 15 of the two-phase erecting motor 2! by leads51. Phase winding 16 is connected across the alternating currentsource T! by virtue of leads 6?, i8 and ground connections 66 and 19.

Coils 35 and 3'! being differentially connected, voltages induced therein by virtue of exciting winding 33' will be in phase opposition and when equal voltages are induced (that is, when the pendulum is on true vertical and the air gaps between discs! and cores '29, 30, 3! and 32 are equal), the resultant voltage across coils 35 and 31 is zero, hence thevoltage in phase winding I5 is zero and motor 2| is at rest. The direction and amount of the torque produced. by the motor therefore are a function of the direction and amount of displacement of the pendulum along the vertical plane containing the axis l9.

Similarly, the coils- 34 and 36 are connected differentially in serie to posts 53 and 6B which are connected by'leads 6i and 62 to a control amplifier 63, theoutput of which is connected by leads B4 to phase winding 81 of the two-phaseerecting motor 20 which rotates aboutthe axis I8; Phase winding 82 is connected across A. C. source Tl throughlead E8, 83 and ground connections 66, 84. Power is supplied to the amplifiers 56 and'63 from source 11, one side of which is indicated as grounded at 66 and the other side of which is connected by leads 6'! and 68 to the amplifiers 56 and 63', respectively. The lead 68 is also connected to a post 69 which is connected by a lead i0 to one side of the center coil 33, the other side of which is grounded at H.

It. will be seenthat .thecoilv 33 constitutes the exciting winding. for the magnetic circuit and that voltages will be induced in the windings 34,

35, 36 and 31 which vary in accordance with the flux threading the various coils, which in turn depends upon the position of the pendulum disc 47!.- In this way precessing torques are produced which tend to keep the pendulum erected.

When the pendulum and erecting system above described is used'in a gyro-vertical system, the motors 23 and 2!, will obey off-vertical signals from the pendulum through the novel electromagnetic circuit which is the subject matter of the present invention, so that the gyro may be restored to the vertical.

The novel pendulum electro-magnetic erection circuitand torquing system herein described does not depend on the use of a gyro to indicate the vertical and to restore the pendulum to true vertical, and it is an important feature of the inven .tion that-the pendulum itself may be used as a vertical;v reference. The pendulum herein d scribed, being sealed in-a damping fluidcan be given suflicient period, depending upon the vis- .cosity of the damping fluid, to permit its use as a vertical reference even under conditions of acceleration as are encountered in aircraft.

Although a specific embodiment has been shown for purposes of illustration, it is to be understood that the invention is capable of varioususes and that-changes and modifications maybe made therein as will bereadily apparent to a person skilled in the. art. The invention is to be restricted only in accordance with the scope of the following claims.

What is claimed is: 1. In a vertical seeking system, a closed pendulurn housing comprising a case forming a cham her and a tube extending upwardly therefrom, a pin fixed to said case and projecting upwardly in said tube, a magnetic member in said case havinga centralupwardly projecting pole piece and a plurality of outer upwardly projecting pole pieces peripherally displaced therearound, a pendulum comprising a tube having a bearing at its upper end hung on said pin for pivotal movement and a magnetic member carried by the lower'end of said last tube adapted to close the mag neticipa ths between said central pole pieces and said outer pole pieces, said last magneticmetm her having a surface spaced from said outer pole pieces to form gaps which are varied as thependulum swings insaid case. i

2.- In a vertical seeking-system as defined in claim 1, an energizing winding on said central pole piece, pick-up windingson said outerpole pieces, erecting motors connected to apply erecting forces to said housing about the coordinate axes of the system and channelsconnecting oppositesetsof pick-up. windings to control the operation of said erecting motorsin accordancewith thedifferentialeffect thereof soas to maintain said-housing in erect position. v

3. A vertical seeking system as set forth in claim 1. in which. said second magnetic 'member comprises a disc having a diameter corresponding to. the spacing of said outer pole pieces .and adapted normally to hang centrally thereof.

4.,A-vertical seeking system as ,-.set forthin claim 3 in which said disc has a horizontal lower surface registering with said central pole piece and tapering toward the periphery to swing over said outer pole pieces.

5. A vertical seeking system as set forth in claim 1 in which said housing is oil filled for damping said pendulum.

6. In a vertical seeking system as set forth in claim 1, a gyro housing having a central vertical bore therein, said pendulum housing being mounted below said gyro housing with said first tube extending upwardly in said bore.

'7. A vertical seeking system comprising a pendulum mounted for oscillation in any direction, said pendulum including an elongated tubular member pendulously weighted at one end, an elongated pin member pivotally supporting said pendulum, a base member, means for mounting said pin member to said base member, said base member being adjustable horizontally about coordinate axes centered at the vertical axis of said pendulum, torquing means associated with each of said axes to shift said base member therein, and means for energizing said torquing means in accordance with departures of said base member from said vertical axis to restore said base member to said vertical axis.

WLADIMIR A. REICHEL.

JOHN F. EMERSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,679,354 Fairchild Aug. 7, 1928 1,726,643 Borresen Sept. 3, 1929 2,367,465 Kunzer Jan. 16, 1945 2,392,370 Esval et al Jan. 8, 1946 2,446,180 I-Iaskins, Jr Aug. 3, 1948 

